Ignition system



March 27, 1928. 1,864,338

- H. c; wALTERs E'r-AL IGNITION .SYSTEM v Filed June 24. 1926 clearlyshown.

Patented Mar. 27, 1928.' 4'

UNITED STATES PATENT oiFlCE.

HERBERT G. WALTERS .AND JOHN T. FITZSIMMON S, OF DAYTON, OHIO,ASSIGNORS, BY

MISNE .ASSIGNMENTS,. T DELCO-REMY CORPORATION, OF DAYTON, OHIO, A. COR-rp'nArIoN or n-LAWARE,

IGNITION SYSTEM.

` .application filed June 24,'1928, Serial .'No. 118,301.

This invention relates to ignition apparatus for multicyli-nder engines,and includes among its objects the providing of 'ignition A apparatuswhich will fnrni'sh ignition Sparks in relatively rapid sucoession.Further obects and dvantages 'of the present invention will be apparentfrom the following description, reference being had to theaccompanying'drawings,l wherein a preferred form of the presentinvention is In the drawings: r .Fig. 1 is' a wiring' diagram'illustrating a form of the present invention;

Fig. '2 is a diagram/illustrating the se- Vquence of operation of thedifferent circuit breakers of an ignition system a'dapted fo'r` aneight-cylinder engine; and

Fig. 3 is a diagram similar to Fig. 2, illustrating the adaptation ofthe invention to a twelve-cylinder engine.

Referring to the drawings, 20 designates an internal-combustion enginehaving a plurality of cylinders, for example, eight cylinders, eachprovidedv with a spark plug. In Fig. 1 the various spark plugs are'numbered from 1' to 8, inclusive, respectively. For example, the smallvcircle referred to by numeral 1 in Fig. 1 designates the spark plug forcylinder #1. The engine 20 drives at cycle speed a shaft 21 which drivesan ignition timer vshaft 22 at one-half1cyc1e speed through the geartrain 24, 26, and which drives an ignition timer shaft 23 at one-half ccle speed through the gear train 25, 27.

ycle speed refers to the time required for the englne to complete onecycle of operation. If,` for example, the engine has eight 'cylinders,cycle speed r'fers to the time required for exploding all of thecylinders;

If the engine is a four-stroke-cycle `engine,'

the shaft 21 would be operated at o ne-half engine crankshaft speed. Ifthe englne 1s a two-stroke-cycle engine, the shaft 21 wouldbecperated'at engine speed. As the present invention is applicable to.two-cycle and fourcycle internal combustion `engin, an engine drivenshaft operated at cycle speed is taken as a basis for defining the speedof the timer shafts 22 and 23 relative'to the speed of the engine. Theshaft 22 rotates in the 'Wire 74 and'a switch 76 with a batterydirection of the arrow 22a, and drives an ig-v nition timer cam 32having equally-spaced cam lobes 34, N being the number of enginecylindcrs, and C the number of ignitio'n .coils used. An S-cylinderengine having its lg'nition provided by two czoils will require a timercam 32 having four lobes 34. Thelobes 34 cooperate with rubbing blocks36 and' 38 of a pair of circuit breaker levers 40 and.46, respectively,upon a' breaker plate reprcsented by the 'Circle 48. The circuit breaker'40 carries a contact 50 cooperating breaker plate 48, and a laf spring64 conducts current from a terminal 66 to the lever 42 and contact 60and yieldingly urges the contact 60 toward the contact 62, and therubbing block 38 toward the cam 32. The terminals 56 and 66 are'connected withA the and'42, respectively, which are pivoted at 44primary winding 72 of an ignition coil 70.

The primary winding 72 is connected which is grounded at 78. T hesecondary w1nd1ng of the ignition coil 70 is grounded through thebattery 77 and is connected with a double-ended rotor 82', each end ofwhichfextendsthe same distance from the center of rotation and serves asa member ,for distributing sparking impulses to any one of the' fourdistributor terminals 84 which are carried by a distributor head 86.These distributor terminals have an an'gular spacing of degrees, forexample, 45

in ignition apparatus for an 8-'cylinder-engine and using twocoils. Asthe distributor 86 serves only one-half the-total number of engine sparkplugs, for example, spark plugs.

2, 4, 6, and 8, the distributor head 86 may carry only four terminals84. For conventates in a clockwise direction, as indicated by the arrow22a, and will cause the breaker 40 to close and open while the breakcr42 rei Vmams open, and hkewlse, Will cause the breaker 42 to close andopen while the breaker 40 remains open. In Fig. 2, the horizontal lines40 represent diagranimatically the periods during which the breakervlever 40 is in closed position, and the horizontal space betweenadjacent ends of these lines 40 represents the period during which 'thebreaker lever 40 is in open position.

Similarly, the horiz'ontal lines 42 in Fig. 2 represent the periodsduring which the breaker lever 42 is in closed position and the spacebetween adjacent ends of the lines 42 represent the periods during whichthe breaker lever 42 is in open position. The dot designated #2 at theend of one of the lines 40 represents the instant of the generation of asparking impulse in the ignition coil 70. This particular dot' isreferred to by #2 since it represents the 'sparking impulse for cylinder#2. At the instant the lever 40 opens1to separate contacts 50l and 52,one of the Aen-ds of the double-end vrotor -82 will be opposite thedistributor terminal #2, so that the Sparki-ng impulses generated willbe distributed to the spark plug #2. As represented in Fig. 2, thebreaker lever 42 will close and open to produce the generationv of asparking impulse in coil at the instant represented by the dot #4 whichrepresents the instant of generation of a. sparking impulse for spa-rkplug #4. Similarly, the breaker lever 40 will close and open to causethe ignition coil to generate a sparking impulse for cylinder #6represented by dot #6 in Fig. 2, and thenbreaker 42 will close and opento cause the coil 70 to generate a sparking impulse for cylinder #8represented by dot #8 in Fig. 2. At the instant the sparking impulse forplug #6 is generated, the rotor 82 will be opposite the distributorterminal #6, and then opposite terminal #8 when the sparking impulse forplug #8 is generated. If the arm 82a of the rotor 82 has beendistributing during one cycle of operation of the engine,

'as represented by the horizontal distance between the arrow heads a andb in Fig'. 2, duringv the next succeedin cycle distribution willbe'efi'ected by the 'iametrically opl,posite arms 82h of the rotor 82.

. Having' described in detail how ignition is .provided 'for spark plugs2, 4, 6, and 8, it. 'a will'be readily apparent from the drawingdirection, as indicated by nulneral 33a. The' brcaker lever 41 isControlled by the cam 33 in order to cause an ignition coil 71 to genierate sparking impulses for spark plugs numbers1'and 5 which areconnected, as shown, with certain of `the distributor termlnals of adistributor head 87,11amely, the

terminals marked #1 and #5. 'Similarly, .the breaker level' 43 isoperated by the cam 33 in. order to cooperate With the ignition coil 71to effect the generation of the spark- 'ing impulses for spark plugs #3and #7 which are connected, as shown, with those distributor terminals85 which have been marked #3 and #7, respectively. The breaker lever 41effects the closing and separation of its contacts, while the contactscontrolled by lever 43 are opened, and the lever 43 effects the closingand opening of its contacts, while the contacts a'fi'ected by lever 41are open. The levers 41 and 43 are arranged to be closed and openedalternately by the cam 33 in order that a suceession of Sparks will begenerated by the coil 71 for the plugs 1, 3, 5 and 7.

In Fig. 2 the horizontal lines 41 designate the closed periods of the-breaker lever 41, and the dots #1 and #5 represent successive instantsof opening of the lever 41 in order to effect the generation of sparkinginlpulses for spark plugs #1 and #5, alternately. In F ig. 2 thehorizontal lines 43 designate the closed periods of the breaker lever 43and the dots numbered 3 and 7 designate, rcspectively, the instants ofthe generation of sparking impulses for the spark plng's 3 vand 7. Therotor 83 operated by the shaft 23' is likewise double-ended, that is,provided with oppositely-extending ends 83a and 83h, which areequidistant from the axis of rotation of the rotor. zAt the instantrepresented by the dot #1 in Fig. 2, one of the rotor ends 83a, forexample, will be adjaccnt the distributor terminal #1. Similarly, at theinstant of the generation of Sparks representcd by the dots #3, #5 and#7, the distrihutor end 83a will be opposite the distributor terminals#3, #5 and #7, respeetively. Since the rotor 83 operates at one-halfcycle speed,

the rotor ends 83a and-83b will operate alternately in distributingasuccession of Sparking impulses to the distribntor terminals 1,

3, 5 and Referrmg to Fig. 2 again, it will be noted that the timing anddistributingsmechanisms associated with the shafts 22 .and 23 functionalternately. Considering one cycle of the engine as being lthe periodbetween successive explosions of c-ylinder '#1 it will be noted thatbreaker 41 first opens to effect the generation of sparking im ulsefor-plug #1, breaker 40 then opens to e ect the genei'tion 'of asparking 'impulse for pl-ug #2. These Operations are'then followed bythe opening of breaker 43 for plugy #3; opening -of breaker 42 for plug#4; opening of breaker 41 for plug #5; opening of breaker 40 for plug#6; opening of. brcaker 43 for plug #7; and opening of'breaker 42 forplug #8.

The zig-zag'dot-and-dash line 'is applied only to direct the attentionmore clearly to the order of the opening of the breaker lcvers. Theclosing periods of the succcssively-operating breakers' overlap, forexample, the closing periods of levers 41 and 40; 40

'and 43; 43 and 42 ;v and 42 and 41. The present .arrangement of circuitbreakers and cams causes the energizing of one of the `ignition eoils tobegin while the other ignition coi-l is building up and thendiseharging. In this manner, the time for energizing the coils 'may beincreasedV beyond that which would be possible if but a single coil wereused to provide ignition impulsesfor all of the en,- gine cylinders. i

It will be understood that the engine 20 may have any desired explosion`orl firing order, for example, the order 1,2, 3, 4, 5, 6,

7 and 8. If the firing intervals are equal, an

.explosion Will be required every onez-.ei'ghth of the total enginecycle period. If, for example, ignition is required'for an 8-cylinder,two-cycle internal-combustion engine capable of Operating at 6000 R. P;M., the vinterval between successive Sparks would be 1/800 of 'a second.By using two coils whichare discharged alternately each coil is causedto generate sparks every 1/400 of a second, which is a rate-within thepossibilities of an ignition coil. As the timing mechanism must beoperated at a relatively high rate in order to meet these ignitionrequirements it is desirable to use breakers in parallel and operatethem alternately. The wear on the rubbing blocks and contact points isthu's distributed and the life of the timing mechanism is substantiallydoubled. "The use of breaker levers in parallel also fpermits the use ofa relatively small cam since the number of lobes is only one-half thenumber required if av single breaker lev'er Were used.

` The Shape of the cam lobes can be made such as to produee the minimumof wear upon the rubbing blocks. i. f

The present invention is adapted for engines having asymmetric firing`intervals as well as engine having cqual firing intervals. By'*asymmetric is meant, firing intervals which are alternately equalinstead of successivel'y equal. VIf the firing' intervals are all equal,then the timing and distributing mechanism associated with the shafts 22and '23 are operated alternately at equal'successivev intervals, forexample, for a two-cycle cylinder engine the intervals between thesuccessive Sparks are 1/8 of a revolution of a shaft, such as 21,rotating at cycle speed, or every 45 of rotation of shaft 21. Sinceshafts 22 and 23 operate at one-half cycle speed, the Operationsvproduced by shaft 22 are 221/2 out of phase with the correspond-` ingOperations produeed by shaft 23. If, for example, the engine is a 60,V-type, 8-cylinder engine requiring firing intervals of 60 and 30alternately, the Operations produced by shaft 22 are 15 out of phasewith the corresponding Operations produced by shaft 23. The intervalbetweensparks 1, 3, 5 and '7; and 2, 4, `(land 8 is of rotation oflshaft 21 or cycle operatiom'but the interval between Sparks 1 and 2 maybe 30, for example, between #2 and #3, 60; #3 and #4, 30, etc.,referring to rotation of shaft 31..

It .is also apparent that the present invention is not limited toproviding ignition for an S-cylinder engine, but is applicable tocngines having any number of cylinders such as 6,- 12, 16 and 18cylinders, and the like.

Th'e following table shows various examples of the applications of thepresent in-' vention to multicylinder engines having regular firinglntervals.

Number Distrlbu- Relativ- Number of coils, tor terity of of eylneams,lobes mina] timer ders=N distrbu- NIC spacing shafts tors=C 180 C/N180/N Fig. 3 shows thevsequence of operation of three pairs of breakerlevers operated by three cams, respectively, and controlling three coilsrespectively, each providing ignition' impulses 'for 'one-third of theengine cylinders. The dots designated7#1 to #12 im represent theinstants of the sparking im- IZF) #12 are provided 'by a third coilwhich is controlled by a third pair of circuit breakers.

The pairs of circuit breakers are out of phase the sparking impulsesAfor by of engine cycle rota-tion or 15 of timer shaft rotation.

While the form of embodiment of the present inventimas herein disolosed,con- 5 stitutes a preferred form, it is to be under- Stood that otherforms might be adopted, all

coming within the scope of the claims which follow.

VVhat is claimed is as follows:

1. Ignition apparatus for a multic linder internall combustion enginehaving cylinders, comprising inf combination, a current source, Cignition coils each for providing tim'er cams each having g lobes andoperated cylinders, C

i at one-half cycle speed; and a pair of circuit make-and-break devicesoperate'd alternatel by each cam, each pair of make-and-breai:

devices controlling the energizing and discharging of one ignition coil,means driven by the engine for causing the cams to oper- F atealternately to eflect the 'discharging of 2** the coils in recurrentsequence, and means for distributing the sparking impulses produced tothe engine spark plugs in recurrent sequence.

2. Ignition apparatus according to claim e C distributor heads eachhaving distributin terminals for connection With the spar C N andcooperating, respectively, with distributing rotors each connected withan ignition coil and operated at one-half cycle speed, the rotorsdistributing alternately in recurrent sequence to their respectivedistributor terminals.

3. Ignition apparatus according `to claim 1, in which the distributing`means conrises plug of cylinders and space'd two distributor heads eachhaving distributing terminals for connection with the N 180 C sparkplugsof C- cyhnders and spaoed degreos 'and cooperating, respectively,With double-end. distributing rotors each connected With an ignitioncoil and operated at I 1, in which the'distrib'uting means comprises 30one-Half cycle speed, the rotors distributing alternately in recurrentsequence to their respective terminals.

In testimony whereof we hereto aflix our signatures.

HERBERTU. WALTERS. JOHN T. FITZSIMMONS.

